1. Field of the Invention
The invention relates generally to photographic cameras and in particular to those cameras adapted to receive a film cartridge in an axial direction. More particularly, the invention relates to a camera which can be loaded with a film cartridge by simple axial insertion of the cartridge into the camera without the need to touch or manipulate a film leader projecting from the cartridge.
2. Description of the Prior Art
In known bottom-loading 35 mm cameras, the film cartridge is received in an axial direction through a bottom opening into a loading chamber of the camera. At the same time, the film leader projecting from a light-tight opening in a throat portion of the cartridge is received longitudinal edge first in an elongate opening at the rear of the camera. The elongate opening extends between the loading chamber and a film take-up chamber in the camera. Typically, some difficulty has existed in loading the film cartridge in such a camera. For example, in the Leica M4 series and the later M5 series, the normally curled leader must first be manually uncurled. Then, with the leader held straight, the cartridge is inserted in an axial direction through a bottom opening into a loading chamber in the camera. At the same time, the leader is inserted longitudinal edge first into a guide slot connecting the loading chamber and a film take-up chamber. In the Leicas, the loading chamber is shaped to constrain the cartridge with the light-tight opening in the throat portion of the cartridge facing in the direction of film advance to the take-up chamber. An attempt to axially insert the cartridge into the loading chamber without first manually uncurling the leader will cause the forward longitudinal edge of the full width (uncut) section of the leader adjacent the throat portion to jam against the bottom of the camera. This will prevent further insertion of the cartridge into the loading chamber without tearing or otherwise damaging the leader. Thus, in the Leicas, film loading requires a certain amount of manual dexterity and care must be taken to ensure that the leader is held straight.
More recently, bottom-loading 35 mm cameras have been devised which include integral means for automatically uncurling the film leader as the cartridge is inserted axially through the bottom opening into a loading chamber in the camera. For example, in commonly assigned U.S. Pat. No. 4,332,452, granted June 1, 1982, the automatic uncurling means comprises a quarter-round corner located adjacent the loading chamber in the camera and an inclined straight edge extending generally along the bottom of the camera. When the cartridge is initially inserted into the loading chamber, the full width (uncut) section of the leader adjacent the throat portion of the cartridge is pushed against the quarter-round corner. The quarter-round corner in turn deflects the full width section of the leader to position the reduced width (cut) section of the leader forward of the full width section crosswise against the inclined straight edge. Then, with continued insertion of the cartridge into the loading chamber, the reduced width section of the leader is progressively straightened by its movement against the inclined straight edge.
Although known bottom-loading 35 mm cameras which include automatic uncurling means for the film leader appear to work satisfactorily, the structure in the camera comprising such means may tend to increase manufacturing costs to a significant extent.